For several years we have been interested in obtaining a true life span understanding of age differences in personality traits from the perspective of the Five-Factor Model of Personality (FFM). In last year?s report we presented findings for a large sample of elderly Medicare Patients from 3 different states in the northeast US. Despite the fact that one might expect to find changes in personality in the extreme old because of changes in health status and major life events such as the death of a spouse, four of the five major personality factors showed no significant age differences between those under age 80 but 65 or older and those over 80 in frail, undereducated Medicare recipients. Only the Agreeableness versus Antagonism factor was higher in 80-100 year old participants. In addition the age difference of those over 80 compared to those under 80 was greater for males than females. The major implication of these cross-sectional findings is that, with the exception of a tendency to become more agreeable, there is little evidence to expect major differences in personality even among individuals in the last decades of life. This is an important finding as it highlights the stability of personality despite the likelihood that older individuals are undergoing several physical and cognitive changes. Hence, personality assessed earlier in life can still serve to inform geriatricians and psychiatrists of the vulnerabilities and strengths patients will possess even when they reach advanced old age.[unreadable] At the other end of the life span, methodological issues regarding the suitability of adult instruments for assessing personality traits and age differences in FFM traits need to be addressed. Use of the Revised NEO Personality Inventory (NEO-PI-R; Costa & McCrae, 1992) in adolescent samples has shown that a few respondents have difficulty with a subset of items. We identified 30 items that were not understood by at least 2% of adolescent respondents and 18 additional items with low item-total correlations, and we wrote 2 trial replacement items for each. We used self-report and observer rating data from 500 respondents aged 14 to 20 to select replacement items. The modified instrument retained the intended factor structure and showed slightly better internal consistency, cross-observer agreement, and readability (Flesch-Kincaid grade level = 5.3). The NEO-PI-3 appears to be useful in high school and college samples and may have wider applicability to adults as well.[unreadable] Another study examined the issue of the psychometric characteristics and suitability of the NEO-PI-3 to a life span sample of individuals from young adulthood to very old age. Data from adults aged 21 to 91 showed that the NEO-PI-3 functions as well or better than the NEO-PI-R in adults. Age trends from combined adolescent (n = 500) and adult (n = 635) samples confirmed previous cross-sectional findings and demonstrated the importance of studying age changes especially at the facet level and during the decade of the 20s. Normative data for self-report and observer rating forms for adolescents, younger and older adults, and all adults are discussed, as well as for a combined-age group. It is argued that combined-age norms may be most appropriate for depicting the personality scores of individuals, but the utility for some purposes of within-age group scores is also acknowledged.[unreadable] [unreadable] Personality trait development in adulthood and old age[unreadable] [unreadable] Although the main outline of age changes in personality traits is known, many uncertainties remain. There is a need to clarify and refine the description of the longitudinal course of personality trait development in adulthood.[unreadable] [unreadable] Last year we examined age trends in the five factors and 30 facets assessed by the Revised NEO Personality Inventory in Baltimore Longitudinal Study of Aging data (N = 1,944; 5,027 assessments) collected between 1989 and 2004. Consistent with cross-sectional results, Hierarchical Linear Modeling analyses showed gradual personality changes in adulthood: a decline up to age 80 in Neuroticism, stability and then decline in Extraversion, decline in Openness, increase in Agreeableness, and increase up to age 70 in Conscientiousness. Although most facets showed curves similar to the factor they define, some did not, particularly within the Extraversion domain. Men and women showed similar curves and cohort effects were modest.[unreadable] As important and impressive as those results are that study is not without limitations. The longitudinal period was only 15 years. What would a much longer longitudinal interval reveal, for example, 30 or 40 years reveal? To address that important question, we examined developmental trends in personality traits over a 42-year time period from the longitudinal trajectories of Guilford-Zimmerman temperament survey scores from the Baltimore Longitudinal Study on Aging (N = 2,359; individuals aged 17-98), collected from 1958 to 2002. Hierarchical linear modeling analyses revealed cumulative mean-level changes averaging about 0.5 SD across adulthood. Scales related to extraversion showed distinct developmental patterns: General Activity declined from age 60 to 90; Restraint increased; Ascendance peaked around age 60; and Sociability declined slightly. Scales related to neuroticism showed curvilinear declines up to age 70 and increases thereafter. Scales related to agreeableness and openness changed little; Masculinity declined linearly. We found significant individual variability in change. Although intercepts differed, trajectories were similar for men and women. Attrition and death had no effect on slopes. This study highlights the use of lower order traits in providing a more nuanced picture of developmental change.[unreadable] The results of these two longitudinal studies are consistent with cross-cultural patterns of age differences observed in cross-sectional studies, supporting the view that these maturational trends are universal. The study of normative trends provides a reference point against which to examine individuals with distinct patterns, which might be due to genetic factors, life experience, or disease, such as Alzheimer?s disease or depression.[unreadable] It should be noted that a couple of recent meta-analyses come to slightly different conclusions than the present results. Meta-analyses are not infallible. In fact, serious problems with meta-analyses have been recognized in medical applications where results often differ from those obtained from the medical gold standard: large randomized control trials. Our guiding belief is that scientific issues are resolved by using sound judgment in reading the literature and by designing new studies that address limitations identified in existing studies. To that end, longitudinal studies of ethnic minorities and non-Western cultures are needed. Studies are needed to shed light on the origins of normative age trends. Future research in community or epidemiological investigations (e.g., ECA) should be making as a high priority investigation of the causes of the modest changes that occur in personality traits in adulthood.